Bulls thundered into and trampled several thrill-seeking runners as they raced down the dew-slicked cobblestone streets of Pamplona on Sunday during the second day of the weeklong San Fermin bull-running festival but no one was gored, officials said.
The second San Fermin feast day is usually one of the most crowded and traditionally features bulls from the Miura breeding ranch, some of Spain's largest and most fearsome fighting animals.
The festivities were made famous by Ernest Hemingway's 1926 novel "The Sun Also Rises."
While many runners suffered minor cuts and bruises, only two persons received medical treatment, one for a bruised back and another for facial contusions, a Navarre regional government statement said.
Early on, a 640 kilogram (1,411 pounds) bull called Navajito, raced ahead of the pack and charged into runners, at one point lifting two which had become caught between the points of its horns but causing no serious injury.
"There were so many people you could barely see the bulls," said Andrew Chavey, 49, from South Carolina but currently working as a contractor with Lockheed Martin in Afghanistan. "It was so fast, and you're almost more afraid of being run over by the crowd of people than the actual bulls, but it was fun."
Some 4,000 revelers took part in the run, San Fermin experts on state broadcaster TVE said.
"It was awesome, fast, overwhelming, extreme and unique," said engineer Ryan Thiel, 33, from New Orleans.
The festival in this northern city dates back to the late 16th century and is also known for its all-night street parties.
The 928 yards (850 meters) runs take place at 8 a.m. daily and are intended to take bulls from stables just outside the city's northern medieval walls to a central bullring where the animals face matadors in the afternoon of each of the feast days.
Despite the Miura's size and musclebound appearance, experts admire them for their explosive acceleration, stamina and grace, characteristics that inspired legendary Italian car maker, the late Ferruccio Lamborghini, to name one of his iconic sports cars after the breed.
Heckle reported from Madrid.